• Title/Summary/Keyword: Optical Trapping

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Study on the efficiency of cleaning Process for Screen printing cleaning (스크린 인쇄 세정에 대한 세정공정 효율 연구)

  • 최성용
    • Journal of the Korean Graphic Arts Communication Society
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    • v.15 no.1
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    • pp.85-96
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    • 1997
  • The color difference between original and printed copy is affected mainly by ink trapping and optical properties of overprinted ink layer. Since the general expression itself about ink trapping is affected also by the optical properties, the analysis of color difference using the ink trapping only cannot be certain. This study will show a new approaching method for optical analysis of spectral reflectance and the effect of printing sequence on color difference in multi-color overprints under the condition of excluding completely the ink trapping problems by means of using transparent film as a substrate.

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Algorithm for Halftone Generation for Gravure Engraving (그라비어 조각용 망점화 알고리즘)

  • 윤종태
    • Journal of the Korean Graphic Arts Communication Society
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    • v.16 no.1
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    • pp.13-24
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    • 1998
  • The color difference caused by the overprinting sequence of ink in multicolor printing is due to both trapping and optical properties of ink layers. Hence the effect of optical properties only cannot be analyzed without removing the effect of ink trapping This study was carrier out for the purpose of analyzing optically the color difference caused by only the optical properties of ink under the various printing sequence. The present optical analysis for overprints showed a good agreement with the experimental result. It is expected that this study may contribute to decreasing the color difference between the original and the printed reproduction in multi-color printing.

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Ultrashort Pulsed Laser Machining for Biomolecule Trapping

  • Choi, Hae-Woon;Farson, Dave F.;Lee, L.James;Lee, Ho
    • Journal of the Optical Society of Korea
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    • v.13 no.3
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    • pp.335-340
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    • 2009
  • Ultrashort pulse laser drilling of polycarbonate track-etched membrane (pTEM) material was used to fabricate a mouse embryo cell trapping device. Holes with a diameter of $2{\mu}m$ to $5{\mu}m$ were fabricated on a $10{\mu}m$ thick membrane using a femtosecond laser with a 150 fs pulse width and 775 nm wavelength and multiple-pulse irradiation. In cell trapping tests, the overall cell occupancy of the machined holes in the fabricated pTEM was found to be more than 80%. The results of a single pulse and multiple pulse irradiation were compared in terms of the surface quality. It was generally found that a single pulse with high energy was less desirable than irradiation with multiple pulses of lower energy.

Calculations of the Trapping Force of Optical Tweezers using FDTD Method (FDTD 방법을 이용한 광집게의 포획 힘 계산)

  • Sung, Seung-Yong;Lee, Yong-Gu
    • Korean Journal of Optics and Photonics
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    • v.19 no.1
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    • pp.80-83
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    • 2008
  • Optical tweezers are a tool that can use a tightly focused laser beam to trap and manipulate micron-sized dielectric particles that are immersed in a medium with lower refractive index. In this paper, the calculation of the trapping force of optical tweezers is presented. A nonparaxial Gaussian beam is used to represent a tightly focused Gaussian beam, and the FDTD (Finite-Difference Time-Domain) method is used for computing the electromagnetic field distributions in the dielectric medium. Scattered-field formulation is used for analytical expression of the incident fields. Using the electromagnetic field distribution from FDTD simulation, the trapping force is calculated based on Maxwell's stress tensor.

Optical Trapping of Microparticles Using a 790 nm Semiconductor Laser (790 nm의 반도체 레이저를 이용한 미세 입자의 포획)

  • 유석진;이진서;안지수;권남익
    • Korean Journal of Optics and Photonics
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    • v.7 no.1
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    • pp.24-27
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    • 1996
  • We describe the optical trapping of yeast particles of $3~4\mu\textrm{m}$ in water solution using a diode laser operating at 790 nm. The yeast particles are trapped by a laser focus and are moved in 2- or 3-dimensions. This confirms the concept of negative light pressure by the gradient force due to the difference of the index of refractions of solutions and particles. By moving yeast particle vertically to the laser beam axis, we measured the horizontal component of the trapping force and compared it with the laser power.

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